What is Creative Commons licensing?

Creative Common Zero (CC0) license is where images has been made available for free usage and the copyright owner has waived all of his/her rights to the work worldwide under copyright law, including all related and neighbouring rights, to the extent allowed by law.

Pictures under the Creative Commons Zero (CC0) license are free for personal and even commercial usage.

• Attribution is not required; however, we do encourage users to give credit to the photographer if possible. Obviously, the photographer has donated the image for free usage so it is always nice to reciprocate with a credit if you can do so. This is not obligatory though, and you can use the images without giving a credit, if you so desire.
• One key restriction is that identifiable people may not appear in a bad light or in a way that they may find offensive (unless of course you actually have written permission from them for this usage).
• You should also not use images with identifiable brand names, property, logos, copyrighted or trade-marked material for commercial advertising. Editorial usage is generally okay as long as it is for news worthy purposes.

The CC0 license was released by the non-profit organization Creative Commons (CC). You can see more information about Creative Commons images and the license on the official page which you can find here:https://creativecommons.org/publicdomain/zero/1.0/